login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A121360 Smallest k such that A002217(k)=n. 1
2, 1, 8, 14, 26, 62, 134, 393, 1257, 4659, 9314, 27933, 167073, 334142, 4677862, 14033577, 56134292, 2133102298, 11788191218, 52541651594 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Least number which becomes prime or 0 or 4 after n-1 iterations of f(x) = sum of prime factors of x (cf. A001414). Agrees with A048133 except for the second term.

a(21) <= 536226160966. a(22) <= 2681130804805. a(23) <= 8512643845707. - Donovan Johnson

LINKS

Table of n, a(n) for n=1..20.

CROSSREFS

Cf. A002217, A001414, A048133.

Sequence in context: A102735 A088960 A263528 * A199928 A047688 A089925

Adjacent sequences:  A121357 A121358 A121359 * A121361 A121362 A121363

KEYWORD

nonn

AUTHOR

Klaus Brockhaus, Jul 27 2006

EXTENSIONS

Edited comment and a(19)-a(20) from Donovan Johnson, Oct 16 2010

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified May 23 19:46 EDT 2017. Contains 286926 sequences.